1. Field of the Invention
The present invention relates to a dual shaft electric device and particularly to such a device in which a dual shaft arrangement is formed by concentric inner and outer shafts, and in which slider supports provided with sliders respectively fixed thereto are attached to the inner and outer shafts for engagement with respective contact patterns.
2. Description of the Prior Art
Conventionally, a dual shaft variable resistor includes an inner shaft connected to a slider carrying contacts adapted to slide across resistance elements carried on a substrate, and an outer shaft also carrying a slider. The slider of the outer shaft carries contacts adapted to slide along resistance elements formed on another substrate, and the two substrates are separated axially of the shafts by a spacer. Recently, such dual shaft variable resistors are assembled by stacking the respective parts on the concentric shafts by means of an automatic machine. However, this method of assembly results in a disadvantage in that the insulating substrate of the variable resistor first placed on the shaft may ride along the shaft with the insulator spacer because it is pushed along the shaft by a spring or the like provided for the slider, so as to make it difficult to position the substrate of the next variable resistor, resulting in difficulty in automatic assembling.